• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.63-70
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• 2012

This study was carried out to investigate change in influent concentration of domestic wastewater flowed from a newly constructed separate sewer system (SSS) and biological nutrients removal efficiency of a full scale Air-vent sequential batch reactor (SBR, $600m^3/d$). The average concentration of $BOD_5$, SS, T-N and T-P from SSS were 246.5 mg/L, 231.6 mg/L, 42.974 mg/L, 5.360 mg/L, respectively which corresponds to 2.2times, 1.2times, 1.8times and 2.1times higher than those from the conventional combined sewer system (CSS). The removal efficiency of $BOD_5$, SS, T-N, and T-P for the Air-vent SBR operated with influent from SSS averaged 99.1%, 99.0%, 91.2%, and 93.5%, respectively. Especially the respective nitrogen and phosphorus removal was 15% greater than that of the SBR operated with influent from CSS. Simultaneous nitrification and denitrification (SND) was observed in an aerobic reactor(II) as a result of DO concentration gradient developed along the depth by the Air-vent system. In order to achieve T-N removal greater than 90%, the C/N ratio should be over 6.0 and the difference between $BOD_5$ loading and nitrogen loading rate be over 100 kg/day (0.130 kg $T-N/m^3{\cdot}d$). Even with high influent T-P concentration of 5.360 mg/L from SSS (compared with 2.465 mg/L from CSS) T-P removal achieved 93.5% which was 15.5% higher than that of the SBR with influent from CSS. This is probably due to high influent $BOD_5$ concentration from SSS that could provide soluble carbon source to release phosphorus at anaerobic condition. In order to achieve T-P removal greater than 90%, the difference between $BOD_5$ loading and phosphorus loading rate should be over 100 kg /day (0.130 kg $T-N/m^3{\cdot}d$).

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.85-91
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• 2014

In this study, the water quality purification of new medias which were NPS media, hyugato, mineral stone, charcoal for applying soil media of Integrated Management Practices (IMPs) of Low Impact Development (LID) were evaluated. The influent concentrations of COD, T-N, and T-P were 117.8 mg/L, 17.1 mg/L, and 2.062 mg/L, respectively. The infiltration capacities of NPS media, hyugoto, mineral stone, charcoal, and gravel were $7.1{\times}10m/s$, $7.3{\times}10^{-5}m/s$, $7.9{\times}10^{-5}m/s$, $6.0{\times}10^{-5}m/s$, respectively. All media meet criteria of infiltration capacity as surface soil layer at IMPs which is over $1.0{\times}10^{-5}m/s$. Maximum removal rates of COD, T-N, and T-P occurred at Charcoal with 98 % of COD removal rate, NPS with 78 % of T-N removal rate, and hyugato with 75 % fo T-P removal rate, respectively. For more high removal efficiency of all water quality item, the mixed media which is 4.5(NPS media): 1(charcoal) : 4.5 (hyugato) as volume ratio was evaluated. The infiltration capacity of mixed media was $7.9{\times}10^{-5}m/s$ and met the criteria of infiltration as surface soil layer. The water quality removal efficiencies of mixed media were very high with showing 70 % for COD, 85 % for T-N, and 71 % for T-P. The mixed media could purify the water quality of surface runoff and was recommended to used at the LID site of ground water quality problem.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.127-135
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• 2002

The accurate evaluation of settlement is important to every steps in the constructions involving soft soils. Relating with those constructions, especially, it has been emphasized recently that the influnce of secondary settlement is important. The ratio of $C_a/C_c$ and the surcharging tests can be applied collaboratively to predicting and reducing secondary consolidation. A series of incremental loading consolidation test and surcharging tests for undisturbed samples of Kunsan clay were performed in this study. As a result of the tests, the ratio of $C_a/C_c$ for the clay was found to be 0.0329. Also, the relationship between void ratio and $t/t_p$ was shown to be linear. Accordingly, the secondary compression index, $C_a for a long term loading had a constant value regardless of time. When the total surcharge ratio was 0.4 and the dissipation ratio of excessive porewater pressure was in the range from 80% to 100%, secondary settlement was effectively reduced for Kunsan clay.

• Journal of Sensor Science and Technology
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• v.7 no.1
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• pp.1-8
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• 1998

We have simulated the operating characteristics of the magnetotransistor(MAGFET) by the finite element method and suggested the optimum design conditions to get a maximum sensitivity, The magnetotransistor has been fabricated by CMOS standard processing according to the suggested design conditions and investigated its electromagnetic characteristics. The sensitivity of the magnetotransistor depends on the ratio of width(W) to length(L) of active area rather than its size, and has a maximum when W/L = 1. The relative sensitivity of a fabricated magnetotransistor was 2.53 %/T.

• Environmental Engineering Research
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• v.25 no.3
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• pp.356-365
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• 2020

The aqueous carbonation efficiencies of basic oxygen furnace (BOF) and ladle slags at various pressures, temperatures, and liquid-to-solid (L/S) ratios were investigated to determine optimum conditions. The maximum CO₂ carbonated concentrations in slag (0.584 mmol/g for BOF slag and 1.038 mmol/g for ladle slag) was obtained at 10 bars, 40℃, and L/S = 5 mL/g-dry. The L/S ratio was the most critical parameter for carbonation. The effect of carbonated slag amendment on the immobilization of heavy metals in two field-contaminated soils was also investigated. The immobilization efficiencies evaluated by using the toxicity characteristic leaching procedure (TCLP) and the Standards, Measurements and Testing Programme (SM&T) were above 90% for both raw and carbonated slags for all soils. The TCLP-extractable heavy metals concentrations were below the criteria (5.0, 1.0 and 5.0 g/L for Pb, Cd, and Cr, respectively) after immobilizations with both slags except for Pb in soil B. The SM&T analysis showed the decrease in the exchangeable phase but the increase in residual phase after immobilization with raw and carbonated slags. The results of this study imply the promising potential of the carbonated slags on the immobilization of heavy metals in the field-contaminated soils.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.176-182
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• 2006

Objective : This study concernes the usefulness of $^{11}C-methyl-L-and$ D-methionine[Met]-positron emission tomography[PET] for glioma grading and detection of recurrence in gliomas, compared with fluorine-18, 2-fluoro-deoxyglucose[FDG]-PET. Methods : Eighty patients underwent Met-PET study for evaluation of glioma : 37 astrocytomas [WHO grade II, 3; III, 8; IV, 26]. 27 oligodendrogliomas [WHO grade II, 16; III, 11]. and 12 suspicious recurrent gliomas. All images were taken within 2 weeks before operation. For suspicious recurrent cases on magnetic resonance images, both FDG-PET and Met-PET were performed. Results : In astrocytoma, Mean maximum standard uptake value[SUV] of region of interest[ROI] was not different between WHO grades [p=0.108]. but ROI/normal contralateral tissue SUV [T/N] ratio was statistically different between WHO grades [p=0.002]. T/N ratio was more closely related to visual scale than maximum SUV of ROI [p<0.001 and p=0.107 respectively]. In oligodendroglioma, there was no statistical difference between WHO grades in view of maximum SUV and T/N ratio. For recurrent gliomas, sensitivity of FDG-PET and Met-PET was 25% and 100%, while specificity of FDG-PET and Met-PET were 100% and 80%, respectively. Conclusion : Met-PET might be an appropriate tool for tumor grading in astrocytoma and be more sensitive for detection of recurrence in gliomas than FDG-PET.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.119-125
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• 2006

The present study including two experiments was designed to determine the effect of media containing different rare earth elements (REE) on proliferation and fatty acids accumulation in 3T3-L1 cell cultures. In Experiment 1, 3T3-L1 preadipocytes in 96-well plates ($1.5{\times}10^4cells/ml$) were cultured with Dulbecco's modified Eagle's medium (DMEM) containing 10% fetal bovine serum (FBS) for 24 h. Then the media were changed to the following 10 different media for 48 h: DMEM containing 10% FBS for the control; the above media containing $5{\mu}M$, $10{\mu}M$ or $15{\mu}M$ of $LaCl_3$, $CeCl_3$ or the mixture of these REE chlorides. The proliferation rate of the cells was measured and compared by a non-isotope method-XTT method. In Experiment 2 the cells in 24-well plates ($1.5{\times}10^4cells/ml$) were cultured in DMEM containing 10% FBS for 7 days until confluent and then were changed to above DMEM containing dexamethasone, methyl-isobutylxanthine and insulin (DMI) for two days. Afterwards the media were changed to the 10 different media with REE supplements as in Experiment 1 and cultured for 6 days. The cells were then harvested for fatty acids analysis by gas chromatography. It was found that supplementation of La (5, 10 and $15{\mu}M$), Ce ($5{\mu}M$ and $15{\mu}M$) and the mixture REE (5, 10 and $15{\mu}M$) stimulated (p<0.05) the proliferation of 3T3-L1 preadipocytes (Experiment 1). In the differentiating 3T3-L1 cells supplementation of La ($5{\mu}M$ and $10{\mu}M$), Ce ($5{\mu}M$) and the mixture REE ($5{\mu}M$ and $15{\mu}M$) decreased (p<0.05) the concentration of monounsaturated fatty acids (MUFA) per $10^5cells$, while the supplementation of La ($5{\mu}M$), Ce ($5{\mu}M$) and the mixture REE ($15{\mu}M$) increased (p<0.05) the ratio of saturated fatty acids (SFA) to MUFA. These results indicate that the supplementation of REE to the media may affect proliferation, differentiation and lipogenesis rates of 3T3-L1 cells. However, the effect may depend upon the level or type of REE applied.

• Journal of Korean Neurosurgical Society
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• v.57 no.4
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• pp.235-241
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• 2015

Objective : Magnetic resonance imaging (MRI) of chronic subdural hematoma (CSDH) detects various patterns, which can be attributed to many factors. The purpose of this study was to measure the level of interleukin-6 (IL-6), interleukin-8 (IL-8), and highly specific protein [beta-trace protein (${\beta}TP$)] for cerebrospinal fluid (CSF) in CSDHs, and correlate the levels of these markers with the MRI findings. Methods : Thirty one patients, treated surgically for CSDH, were divided on the basis of MRI findings into hyperintense and non-hyperintense groups. The concentrations of IL-6, IL-8, and ${\beta}TP$ in the subdural fluid and serum were measured. The ${\beta}TP$ was considered to indicate an admixture of CSF to the subdural fluid if ${\beta}TP$ in the subdural fluid $({\beta}TP_{SF})/{\beta}TP$ in the serum $({\beta}TP_{SER})>2$. Results : The mean concentrations of IL-6 and IL-8 of the hyperintense group (n=17) of T1-WI MRI were $3975.1{\pm}1040.8pg/mL$ and $6873.2{\pm}6365.4pg/mL$, whereas them of the non-hyperintense group (n=14) were $2173.5{\pm}1042.1pg/mL$ and $2851.2{\pm}6267.5pg/mL$ (p<0.001 and p=0.004). The mean concentrations of ${\beta}TP_{SF}$ and the ratio of ${\beta}TP_{SF}/{\beta}TP_{SER}$ of the hyperintense group (n=13) of T2-WI MRI were $7.3{\pm}2.9mg/L$ and $12.6{\pm}5.4$, whereas them of the non-hyperintense group (n=18) were $4.3{\pm}2.3mg/L$ and $7.5{\pm}3.9$ (p=0.011 and p=0.011). Conclusion : The hyperintense group on T1-WI MRI of CSDHs exhibited higher concentrations of IL-6 and IL-8 than non-hyperintense group. And, the hyperintese group on T2-WI MRI exhibited higher concentrations of ${\beta}TP_{SF}$ and the ratio of ${\beta}TP_{SF}/{\beta}TP_{SER}$ than non-hyperintense group. These findings appear to be associated with rebleeding and CSF admixture in the CSDHs.

• Journal of Animal Environmental Science
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• v.17 no.2
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• pp.131-138
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• 2011

This study was carried out to investigate on the composting characteristics variation accoding to air supply capacity in Pig manure. The composting of pig manure is economical and efficiently process. The fermented compost was added in pig manure mixed with sawdust was composting reators. Air supply capacity levels of fermented compost on the pig manure mixed with sawdust were regulated at 50, 100, 150 and 200$\ell/m^3$/min. respectively. The obtained results can be followed as bellow; The temperature variations of experimental composting piles during composting for the different of T-1 reach $40^{\circ}C$ in 2 days, T-2, T-3 and T-4 reach $60^{\circ}C$ in 2 days and T-3, T-4 maintained until 8 days. The decreases in water contents per each square meter for the different of T-1 (50 l/$m^3$/min), T-2(100 l/$m^3$/min), T-3(150 l/$m^3$/min) and T-4(200 l/$m^3$/min.), The decreases ratio in water contents was T-1, T-2, T-3 and T-4 were 15.4%, 28.8%, 33.4% and 35.2%. The decreases ratio in weight was T-1, T-2, T-3 and T-4 were 7.6%, 15.6%, 16.8% and 16.9% respectively. The variations of oxygen concentration from composting period in case of oxygen discharge concentration T-1, T-2, T-3 and T-4 were 9 ppm. respectively. Fertilizer components after composting were examined. Nitrogen contents of the T-1, T-2, T-3 and T-4 were 0.45%, 0.44%, 0.42% and 0.44%, and P2O5 contents were T-1, T-2, T-3 and T-4 were 0.37%, 0.41%, 0.42% and 0.44% respectively. Therefore, the compost curing air supply of air volumes at least 150$\ell$/min/min. or more to supply the aerobic composting pig manure normally are judged to be possible.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.511-520
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• 2014

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.